Manually adjustable regulating valve devices for use in railway-type locomotive brake valve equipment have been known from the prior art prior to the present invention. See, for example, U.S. Pat. Nos. 2,958,561, issued Nov. 1, 1960, to Harry C. May and 3,504,950, issued Apr. 7, 1970, to Glenn T. McClure and assigned to the assignee of the present invention. Also of interest to the present invention is a paper titled, "30-CDW Brake Valve Operation and Updating", prepared by Dale A. Chovan, for presentation at The Air Brake Association Annual Technical Conference held on Sep. 18, 1989 in Chicago, Ill. The teachings in each of the above-identified references is incorporated herein by reference thereto.
The locomotive brake valve equipment taught in FIG. 1A of U.S. Pat. No. 2,958,561 includes a sectionalized casing which contains therein a relay valve device, a self-lapping control valve device (adjustable regulating valve), a brake pipe cut-off valve device, a vent valve device, an emergency valve device, a suppression valve device and an equalizing reservoir cut-off valve device. The operation of such self-lapping control valve device, vent valve device, emergency valve device and suppression valve device is controlled respectively by cams. Such cams are spaced axially along and rotatably connected to a cam shaft. The cam shaft is rotatably supported by the casing and, in turn, is rotatably connected to an arcuately moveable brake valve handle. The self-lapping control valve device includes a diaphragm-type piston which is subject on a first side thereof to fluid pressure in a chamber and on a second side thereof to pressure exerted by a helical regulating spring housed in an atmospheric chamber. Such regulating spring is arranged so that it can be manually adjusted from outside the casing as necessary by means of an adjusting screw which adjusts the relative position of a spring retainer seated against such regulating spring. The degree of compression of the regulating spring is adjusted such that the regulating spring will reload the diaphragm piston to a degree that corresponds to the desired full charge pressure value of the equalizing reservoir pressure, and hence of the brake pipe pressure as is understood in the railway braking art. Axially arranged with the diaphragm piston is a main cylindrical slide valve. Such slide valve is sealingly slideable within a bore formed in the cavity. Such bore is open at one end into a first chamber and at an opposite end into a second chamber that is connected to the atmosphere via a vent port. An auxiliary slide valve is telescopingly slideable within a coaxially arranged bore through such main slide valve. A helical spring positioned in such first chamber biases the auxiliary slide valve into contact with the second chamber side of the diaphragm piston. Such spring is backed up by a follower member that is positively connected to the main slide valve and engages a cam so that the position of such main slide valve will be controlled according to the rotational position of the moveable brake valve handle.
The locomotive brake valve apparatus taught in FIG. 2 of U.S. Pat. No. 3,504,950 includes essentially the same components taught in U.S. Pat. No. 2,958,561. Each of these locomotive brake valves is known in the industry as a 26 type brake valve. It can be noted that the self-lapping central valve device used in the '950 reference is a poppet type valve as opposed to the slide valve type used in the '561 reference.
The advanced locomotive brake valve apparatus discussed in the Chovan reference is a now conventional type brake valve apparatus designated 30-CDW in the railway industry. For example, in FIG. 1, in drawing no. 0582799 following page 51, a diagrammatic view of the 30 CDW brake valve is shown, while FIG. 1, on page 8 shows an exploded view of parts of the brake valve. Specific attention is drawn to part no. 1-64 of FIG. 1, which illustrates a regulating and inlet valve unit, to which the present invention is specifically directed.
The adjustable regulating valve device used in the railway locomotive valve apparatus includes a pin housing and a valve spring housing which are threadedly engaged to seal those two components together and enclose a valve pin, spring end enclosure, and a spiral spring. In assembly of the adjustable regulating valve device, an initial threaded engagement of the pin housing and valve spring housing is effected and the assembled unit initially bench tested for leakage. While assembled units have often passed the initial bench test, upon placement into a railway locomotive brake valve, some such assembled units, for some unexplained reason, have shown leakage, which has required the time consuming and expensive removal of the adjustable regulating valve from the railway locomotive brake valve apparatus for disassembly and reassembly for a further leakage test.
It is an object cf the present invention to provide an adjustable regulating valve device for a railway locomotive valve apparatus that is readily assembled and which does not result in leakage following initial bench testing.
It is another object of the present invention to provide a valve spring housing that, when threadedly engaged with a pin housing does not result in leakage therebetween following initial bench testing.